the invention relates to cooling system and more particularly to a system that can be used for cooling the nosetip of a hypersonic weapon during its hypersonic mission.
Rockets, rocket craft and projectiles which are caused to travel through the atmosphere at very high rates of speed are subject to an extreme rise in temperature due to aerodynamic heating. The temperatures thus produced may even be above the melting point of any available metal or other material which is suitable for use in the outer casings of such projected devices.
Several designs and systems have been developed to cool a nosetip of the rockets and projectiles. Most of these use a variation of the heat pipe designs. In U.S. Pat. No. 2,922,291 the inventor discloses a simple metallic jacket with a coolant such as water circulating through it. U.S. Pat. Nos. 3,267,857 and 3,682,100 also use the heat pipe approach with the added advantage of using the endothermic reaction of the hydrides. Another system is illustrated in U.S. Pat. No. 4,739,952 which discloses the use of evaporative material carried in the missile structure which is ejected by vapor pressure through openings in the missiles outer skin and cools the missile as it flows along its outer surface.
Most of the prior art systems require the pumping of fluids at some level of their design. Some of the disadvantages of these types of systems are the fact that liquid systems tend to dynamically shift the center of gravity depending on the flight environment (i.e. acceleration, vehicle attitude, angle-of-attack). Also these systems require pumps for pressurizing the flowing fluid which adds to the requirement for an active system thus decreasing the overall system reliability. The weight of a pumping system will be greatly increased in small vehicles due to the pump and power components (batteries).
It is an object of the invention to provide a novel cooling system for the nosetip of hypersonic weapons that eliminates the disadvantages of liquid systems.
It is also an object of the invention to provide a novel cooling system for the nosetips of hypersonic weapons that eliminates the need for a pump such as is required by active systems that circulate the liquid through them.
It is another object of the invention to provide a novel cooling system for the nosetip of hypersonic weapons that eliminates the additional weight required by active systems that utilize pumps and power components.
It is an additional object of the invention to provide a novel cooling system for the nosetips of hypersonic weapons in the form of a passive system that not only eliminates additional weight but as the sublimation process is occurring the vehicles weight is decreasing thus improving the vehicles performance.
It is a further object of the invention to provide a novel cooling system for the nosetip of hypersonic weapons that not only incorporates the heat capacitants of the endothermic reaction of the sublimating material but also provides for the pressurization of these products for additional sub or supersonic impingement cooling in the localized area of the extremely high temperature stagnation region.